Endocrine System Physiology 3 - Teel Flashcards
Diabetic Ketoacidosis
Kidney transporters have a maximum transporter capacity, and if blood glucose level gets above that, glucose can spill into urine, cause osmotic diuresis
Chronic complications of DM
Diabetic neuropathy
Diabetic nephropathy
Diabetic retinopathy
High blood glucose generally impairs healing. More infections in general.
A1C
Form of hemoglobin that is glycated. Sugar molecules attach themselves to some other molecule, due to high sugar amounts.
Levels greater than 6.5% indicate increased risk of chronic complications of DM.
3 P’s
Polydipsia: thirst
Polyuria: frequent urination
Polyphagia: hunger
Regulation of Plasma Calcium
Amount in ECF should be fairly constant.
Gut absorbs calcium from diet, ECF secrets to gut.
ECF can deposit calcium into bone, can also resorb from bone.
ECF can filter calcium into kidney, and reabsorbed from kidneys.
2 Losses: Urine and feces. Cope with gut / bone
Regulation of Plasma Phosphate:
Same as Calcium.
Role of Osteoblasts
Osteoblast produce IL-6, RANK ligand, growth factors.
RANK ligand stimulates formation of osteoclasts and their activity
Can produce another protein called Osteoprotegerin. This binds to RANK ligand and blocks actions of osteoclasts
This balance between RANK ligand / osteoprotegerin = bone metabolism
Osteoblasts regulate osteoclasts.
Role of Osteoclasts
Bone resorption.
Releases lysosomal enzymes and H+ that dissolve bone.
Osteoclasts sit on top of bone, sealed all around it via sealing zones.
Parathyroid Hormone (PTH)
Comes from Chief cells from spherical masses in thyroid (parathyroid).
Chief cells respond to hypocalcemia (when ca2+ falls below certain level, PTH released)
Hypercalcemia will turn it off, hypocalcemia will turn it on.
Calcium sensors in chief cells monitor plasma Ca2+.
Effects of PTH on Kidney:
Remember: PTH released due to not enough calcium.
Stimulates reabsorption of calcium in TAL and distal tubules
Inhibits reabsorption of phosphate in proximal tubules.
Stimulates Vit. D conversion of proximal tubular cells.
Effects of PTH on Bone:
Stimulates osteoblasts
Indirectly stimulates osteoclasts (bone resorption cuz u need more calcium)
Release of growth factors as bone is resorbed.
Activates calcium channels in osteocytes, promoting transfer of bone fluid to the osteocyte
Effects of PTH in intestine:
Vit. D indirectly stimulated by PTH causes increased absorption of dietary Ca2+.
Synthesis of Vitamin D:
Form of cholesterol in skin, that in the presence of UV light, syntehsizes vit. D.
Vit D3 is the intermediate form.
Vit D2 is from food.
Both are fat soluble, found in mixed micelles in gut lumen and chylomicrons in portal blood.
Vitamins stored in adipose tissue.
Effects of Vit. D:
Can affect gene expression
Acts synergistic with PTH
Stimulatory link between Vit. D. and osteoblast / osteoclast precursors
Important for bone formation.
Proposed benefits of Vitamin D:
Aids regulation of plasma levels of calcium / phosphorus
Promotes cell differentiation*
Anti-inflammatory actions*
Controls BP
Promotes immune function (rumored to prevent COVID)
Helps regulate blood glucose levels*
Reduces risk of many cancers
Anti-depressant.
Vitamin D is more of a hormone than a vitamin.
